Detachable plug



May 18 1925.- 1,585,350

W. H E

DETACHABLE PLUG Filed May 19, 1925.

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hamm/f5 um" g5 Patented May 18,

UNITE.

WILLIAM ILE, OF JACKSON, MICHIGAN.

DETACHABLE PLUG.

Applcation'leld May 19, 1925. Serial No. 31,439.

The invention relates to a detachable plug. The object of the present invention is to improve the construction of detachable plugs through the plug and to provide a simple, practical and etticient detachable plug adapted to be screwed into `a receptacle or other fixture and to be removed therefrom and provided with a removable cap adapted to permit the plug to remain in such receptacle or fixture and todisconnect therefrom the device or appliance which is supplied with electric current from the said receptacle or fixture.

A further object of the invention is to provide a detachable plugof this character in which the parts .vill be rigidly secured in position so that there will be no liability,

of the s`aine becoming loose through the rotation of the plug or the removal and attachment of the cap thereof. i

A further object of the invention is to provide a detachable plug having a ca p body and both of molded bakelite or similar insulating material and adapted to reduce the amount of insulating material to a minimum and provided also with ample air space at the points of attachment and at the contacts for protecting the plug and for preventing arcing.y

lVith these and other objects in view, the invention consists in the construction and novel combination and arrangement of parts hereinafter fully described illustrated in the accompanying drawings and pointed out in the 'claims hereto appended, it being understood that various changes in the form, proportion and minor details of construction,

` within the scope of the claims, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention. f

In the drawings:

Figure 1 is a longitudinal sectional view of a detachable plug constructedin accordance with this invention.

Fig. 2 is a similar view4 taken at right angles to Fig. 1.

Fig. 3 is a plan view of the inner end of the cap.

Fig. 4L is a plan view of the outer end of the body4 of the plug.

Fig. 5 is a similar view of the inner end of the body of the plug.

Fig. 6 is a detail view of one of the terminals of the removable cap.

bedded in the bakelite as 7 is a plan view of the metallic screw shell. v

Fig. 8 is a fragmentary section of the ca illustrating the manner of interlocking the terminals with thel cap.

In the accompanying drawings in which is illustrated the preferred embodiment of the invention the detachable plug comprises in its construction an insulating plug body 1 of molded bakelite or other suitable material, a button or end section 2 of similar material and a metallic shell 3 of brass or other suitable material interposed between the button or end section and the plug body l and constituting a hollow section of the plug. The metallic shell which is adapted to reduce to a minimum the amount of balrelite necessary for the construction of the plug body is provided with a top wall or flange 4L provided with a central oblong opening 5 receiving an oblong'enlargement 6 at the inner .face of the end section or button 2 and interlocking the button and the metallic shell against relative rotary movement. The oblongenlargement 6 of the end section or but-ton 2 is of a Width less than the width of a button and of a length less than the diameter of the same and the flange 4 of the metallic shell extends entirely around the same as clearlyillustrated in Fig. 7 of the drawing. The shell is threaded to screw in; to a socket or receptacle and its inner end portion 7 is smooth and cylindrical and fits in an annular recess 8 formed by reducing the inner end of the insulating body of the plug. The button 2 is provided with a central opening 9 through which passes a center screw 10 provided at its outer end with a head 11 .arranged in a central recess l2 in the outer face of the button 2 and being of polygonal formation to receive` a .wrench or other tool for screwing its inner threaded end 18 into and out of an interiorly threaded bushing 14 which is embedded in the insu-f The interiorly threaded bushing 14 is eman insert during the molding of the body 1 and it is provided at its inner end with an annular iange 15 forming ahead and preferably corrugated as shown for securely anchoring the bushing in the molded bakelite or other insulating material-and for preventing any loosen` ing and relative rotary movement of the bushing and the body 1. l The iange 4 tits no .2 and a metallic section 3 of the body oi the plug firmly together. By providing a hollow intermediate metallic section or shell 3 the bakelite may be made in two sections, namely, the button 2 and the body 1 and the button is firmly supported and connected with the body l without the necessitybf employing an integral connecting portion and at the saine time the hollow interior provides an enlarged air space around the parts and thereby insulates the same. The body 1 is provided at its inner end with opposits rectangular recesses 17 which are adapted to receive an arm or tongue 18 formed integral with the hollow shell and arranged interiorly thereof and consisting of the metal cut from-the end wall or flange of the same to form the oblong opening 5 which receives and interlocks the shell with the button 2. A pair of the recesses 17 is provided to facilitate rigid engagement of the tongue 18 with the body 1 in assembling the parts to the tongue by extending into one of the recesses 17 interlocks the shell with the body and prevents relative rotary movement of the shell and the body 1. The tongue 18 is of a width that fits snugly Within the recesses 17 and the shell by means of the tongue and the opening 5 is inten locked with both of the bakelite sections of the plug and-holds the same against relative rotary movement.

The body 1 is provided with longitudinal openings 19 and it has curved grooves 2O in its outer end face connecting the openings and forming guides for directing terminals 21 to the openings 19 so that when the terminals 21 are placed in the grooves 20 at any point a partial rotary movement of' the terminals and removable cap 22 to which the terminals are secured will carry the said terminals tothe longitudinal openings 19. The longitudinal openings 19 receive a cen ter contact 23 and a shell contact 24 consisting of strips of spring metal and provided with protuberances 25 for engaging with oppositely flared openings 26 in the terminals 21 of the cap 22. The terminals 21 are beveled at their side faces at the openings 26 to fit the cup shaped protuberances formed lin the contacts 23 and 24 and the beveling of the openings 26 and the cup shaped formation of the protuberances will enable the terminals 21 of the removable cap to be readily moved into and out of engagement with the contacts 23 and 24 of the plug and will provide a firm interlocking connection when the parts are engaged so as to insure a perfect electricalycontact. The ends 27 of the terminals 21 are oppositely beveled and the outer ends 28 ot the contacts 23 and 24 are bent laterally to permit the terminals 2l to readily pass the ends of Athe contacts 23 and 24. The longitudinal openings 19 are 'ing plates 30 seated in correspondingly shaped recesses 31 formed in the inner face of the removable cap 22. The removable cap 22 is provided with a central opening` 32 for the passage of the wires which are connected with the terminals 21 by means o'tl binding screws 33 mounted on the attaching portions or plates of the said terminals 21.

rlhe attaching plates are curved at their outer edges to conform to the circular shape ot the removable cap which is provided at -its inner face with an annular wall 34 forming a space or compartment 35 which not only lessens the bakelite employed in the construction ofthe cap, but which provides an enlarged air space surrounding the attached portions or" the terminals 21 and the ends of the wires connected thereto ior both the reduction in the cost of the device and the insulation of the parts, The inner edge of the attaching plate of the terminal is also curved as shown to clear the central opening 32 and the terminals 21 are secured to the removable cap in the recesses 31 by means of screws 3G which engages interiorly threaded bushings 37 embedded in the balielite of the removable cap as inserts when molding the said cap 22. The bushings 37 are provided with flanges 38 preferably corrugated as shown for anchoring the busli ings securely Within the bakelite and for eiiectually preventing any loosening of the bushings through the turning of the screws 3G. In order to relieve the attached portions 30 of the terminals 21 of strain and enable each of the terminals to be firmly attached by a single screw each of the plates 30 is provided at one end adjacent to the screw 36 with an integral lug 39 which is engaged in a recess or extension 40. The lug 39 will interlock the plate 30 with the remoif'able cap and relieves the walls of the recesses 31 of strain. By the particular construction and arrangement of the plates 30 of the terminals 21 the latter are securely fastened to the cap and the latter may be removed and replaced without liability of loosening the parts. To facilitate removing and replacing the cap 22 the latter is exteriorly beveled at 41 at the annular wall or fiange 34 to provide a groove. This will enable the person removing or replacing the cap to grip the latter under the saine and the said cap may be rmly and securely held by the person in removing the same from the plug or in replacing the capvthereon.

lhe center Contact is providedV at its attached end with an arm 42 extending inwardly from the contact and liited against the enlargement or extension 6 and pierced by the center screw 10. The shell contact is provided at its inner end with a lug 43 which extends through a slot 44 in the flange 4 of the shell and engages in a recess or seat 45 in the same. The recess or seat 45 is formed by bending or depressing they flange at the slot 44 as clearly shown inf" Fig. l of the drawings and by this construction the lug 43 may be engaged in the seat 45 and the flange will hold the shell contact in position when the parts are secured together by the center screw 10. The shell contact may be permanently secured .to the flange or the shell if desired.

The center contact is preferably secured to the end section ai'ter the shell has been assembled on the end section. This `attaching means of the center contact preferably consists of a sleeve 46 embedded in the end section and lining the central opening thereof and projecting therefrom a suficient distance to permit the inner end of the sleeve to be expanded in the engagement with the arm of the center contact.

What is claimed is:

l. An electrical attachmenty plug including an insulating body, an end section of insulating material provided with a polygonal enlargement, a metallic screw shell provided with a iiange having an opening receiving and conforming to the configuration of the said enlargement to interlock the shell and the end section, said shell being also provided with a tongue interlocked with the body for holding the parts against relative rotary movement and a center screw connecting the end section and the body and securing the parts together. y

2. An electrical attachment plug including an insulating body, an end section of insulating material provided with a polygonal enlargement, a metallic screw shell provided with a flange having an opening receiving and conforming to the coniiguration of the said enlargement to interlock the shell and the end section, said shell being also provided with a tongue formed integral with the liange by the cutting of the said opening therein and bent into substantially parallelism with the shell and engaged with'the body for holding-the shell and the body against relative rotary movement and a screw connecting the -end section and the body andsecuring the parts in interlocked relation,

3. An electrical attachment plug including an insulating body provided in its inner end with a plurality ofrecesses, an insulating end section, a metallicv sleeve interposed between the body and the end section and forming a hollow intermediate section and provided with a tongue engaging one of the said recesses to interlock the body and the shell against relative rotary movement and a screw connecting the end section and the body and securing the parts together. l

4. An electrical attachment plug including an insulating body provided in its inner end with a recess, an end section of insulating material provided at its inner face with a substantially oblong enlargement, a metallic screw shell provided with a flange having an opening receiving the oblong enlargement to interlock the end section and the shell, said shell being also provided with a tongue extending from the flange longitudinally of the plug and engaged with the recess oi' the body to interlock the plug and the shell and a screw connecting the end section andthe body and securing the parts together.

5. An electrical attachment plug including an insulating body provided in its inner end with a recess, an end section of insulating material provided at its inner face, with a substantially oblong enlargement, a metallic screw shell provided with a flange having an opening receiving the oblong enlargement to interlock the end section and the shell, said shell being also provided with a tongue extending from the liange longitudinally of the plug and engaged with the recess of the body to interlock the plug and Q the shell and a screw connecting the end section and the body and securing theparts together, a center contact secured to the end section by the said screw and a shell contact connected with the flange of the shell.

6. An electrical attachment plug provided with a removable cap having a central opening and having bushings embedded in it at opposite sides of the opening, spaced terminals provided with attachment plates seated within the cap and provided with fastening devices engaging the'said blush` ings, said terminals being also provided with inwardly' extending lugs anchored with the cap.I

7. An electrical attachment plug including a removable cap provided at its inner face with recesses having an extension and spaced terminals provided with attaching plates'vseated in the said recesses and having lugs projecting into extensions in the recesses to interlock the terminals with the cap and means for securing the terminals to the cap.

ln testimony whereof I have hereunto set my hand.

WILLIAM ILE. 

